Thousands of shoppers in the southern Chinese city of Shenzhen fled the area of a 957-foot (291-meter) skyscraper Tuesday, after it inexplicably started swaying.

Videos circulating on Chinese social websites revealed audiences running out of the wobbling construction, with some screaming and looking back over their shoulders.

The weather was nice at the time and there were no reports of an earthquake in the area. No deaths or injuries have been reported.

The SEG Plaza in Shenzhen began to shake around 12:30 p.m. local time. Some 15,000 people were indoors, according to the official paper of the Shenzhen Municipal Communist Party Committee. All those inside were evacuated within 90 minutes, local authorities said.

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Authorities investigating the cause of the shake stated in a statement which no”abnormalities in the primary construction and surrounding environment of the construction” had already been found.

The town’s meteorological station reported that a maximum wind speed of around 20 mph (32 kph) in midday Tuesday — a speed of motion called a”fresh breeze” by the US National Weather Service.

The tower is located in the busy shopping district of Huaqiangbei, home to the largest electronics market in the world. The building houses various local tech companies and a multistory electronics mall.